Downsizing of supermassive black holes from the SDSS quasar survey

Date
Authors
Labita, Marzia
Decarli, Roberto
Treves, Aldo
Falomo, Renato
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Description
Starting from the ~50000 quasars of the Sloan Digital Sky Survey for which MgII line width and 3000 A monochromatic flux are available, we aim to study the dependence of the mass of active black holes on redshift. We focus on the observed distribution in the FWHM - nuclear luminosity plane, which can be reproduced at all redshifts assuming a limiting BH mass, a maximum Eddington ratio and a minimum luminosity (due to the survey flux limit). We study the z-dependence of the best fit parameters of assumed distributions at increasing redshift and find that the maximum mass of the quasar population evolves as log[M_BH(max)/M_Sun]~0.3z+9, while the maximum Eddington ratio (~0.45) is practically independent of cosmic time. These results are unaffected by the Malmquist bias.
Comment: 9 pages, 9 figures. To appear in MNRAS
Keywords
Astrophysics - Cosmology and Nongalactic Astrophysics
Citation
Collections